1. Field of the Invention
The present invention relates to a protocol for reliable transfer of information in a communications network, and in particular, to a reliable output protocol for sending files from one node to one or more other nodes in a network.
2. Description of the Related Art
The brisk pace of development in fixed and wireless telecommunications networks has led to an ever-increasing scope of service and business-support functions supported by these networks. These functions usually require an exchange of information that is tied with value, such as a generated revenue value or any other value deemed critical to a business, government or personal entity. Examples of valuable information exchanged between computer systems include, for example, charging data transferred from a telephone switch to a billing system, fund transfers, tax filings, credit reporting, financial reporting between offices and statistics from the telephony or radio parts of a network that must be collected to optimize network efficiency.
Many new and innovative subscriber services require complex charging schemes. In one new service, “virtual” operators are willing to pay for the right to use telecom equipment owned by other operators. Network operators of these services are demanding fast, almost instant billing (such as with prepaid cards), in which charging data must be processed and made accessible in real-time or near real-time. Real time or near-real time processing of files is also desired in network systems providing detection of fraud, hot billing, subscriber analysis or subscriber crediting services.
At the same time, the implementation of more and more applications on large numbers of small machines has led to an increase in movement of data between business computer systems. Much of this data exchange is performed using file transfer software embedded within business software applications running on these computers. Software designers are often required to include specific interfaces to the file-transfer software in their programs. In addition, these programs frequently deal with matters such as error-analysis, recovery, routing, and receipting, which are more appropriate to communications software than to business applications.
Network operators are finding themselves increasingly burdened as the volume of information switched over their network nodes continues to grow. To cope with rapidly increasing data-processing loads relating to call-charging, and the demand for real-time or near real time accessibility of this data, network operators are increasingly offloading capacity-demanding tasks to external computing systems for subsequent processing. These external systems are generally open standard (e.g., transfer control protocol/Internet protocol (TCP/IP) and open systems interconnect wide area network (OSI-WAN)).
It is imperative that the data not be corrupted, lost or duplicated when valuable information is sent from a source to a destination in a telecommunications network. In the case of charging data from a telephony switch to a billing system, for example, data-loss would imply loss of revenue because subscribers cannot be billed for their telephony usage. On the other hand, data-duplication would imply over-billing of subscribers, which could result in subscribers leaving the operator, bad publicity, and thus loss in revenue. It is therefore vital that the charging information be transported in a reliable, safe way and that control over the information is either at the sending or receiving end (e.g., at a telephony switch or at a billing system). A system transferring valuable data should also have the ability to cope with situations involving problems with the communications link (e.g., when the link is broken) or with any of the two nodes involved (e.g., system crash/restart).
Several things may go wrong as soon as an information file is at and under control of a receiving end device (e.g., a billing system computer) even when one or more files are transferred intact from a local node to a remote node. For example, data can be corrupted during storage of the file on disk or during the process of copying it, which will ultimately result in revenue loss for the operator.
Thus, there remains a need in the art for a file output protocol that safely and reliably transfers files from one network node to one or more other network nodes without loss or duplication of the files and also insures that files that have been transferred remain accessible for retransmission.